(276a) Using Light to Manipulate, Assemble, and Generate Inorganic Nanomaterials in Solution

The fabrication of junctions between colloidal nanomaterials has enabled a wide range of technologies, but, as devices approach the single-nanoparticle scale, the rational assembly of nanomaterials remains challenging. In 2018, Arthur Ashkin won the Nobel Prize for developing optical traps, which offer the ability to manipulate individual nanostructures in three dimensions. However, to date, there are relatively limited reports on optical trapping in non-aqueous media, and thus far, inorganic nanoscale materials have only been optically trapped in vacuum and in aqueous solvents. Here, we present our recently reported work on the use of light to manipulate and generate inorganic heterostructures in non-aqueous solvent systems, including a novel demonstration of the use of optical trapping to manipulate, align, and assemble metal-seeded semiconductor nanowires in organic dispersion, resulting in the fabrication of arbitrarily long heterostructures consisting of periodically repeating, metal-nanocrystal/semiconductor-nanowire junctions. Heat transport calculations and optical images demonstrate that the metal tip of each optically-aligned nanowire undergoes eutectic melting in the optical trap, facilitating the oriented tip-to-tail “nanosoldering” of successive nanowire building blocks. In addition, an exploration of cooperative heating effects will be presented, as well as our recent efforts to monitor the dynamics of nanowire growth in solution.